It's a misnomer to call HPV the "cervical cancer" virus. It has been known for years that human papillomaviruses are associated not only with genital warts and cervical cancer, but also with various other cancers including anal cancer, penile cancer, and cancer of the vulva. In recent years, however, scientists have found a strong association with other types of cancer, too – cancers of the mouth and throat. Some scientists have even hypothesized that by 2020 these cancers could even replace cervical cancer as the most common cancer caused by HPV.
HPV Infection as a Risk Factor
Although, worldwide, most mouth and throat cancers are still associated with tobacco use and/or alcohol, studies have begun to show that HPV may be another major source of risk. HPV seems to be particularly strongly associated with cancer of the tonsils, although it is also found in biopsy samples from other sites nearby.
Unlike with cervical cancer, there are many other risk factors for cancers of the mouth and throat. In areas where those other risks, such as alcohol and tobacco use, are less common, HPV is probably responsible for more cancers than in areas where they are widespread.
A research study published in October 2011 found that the incidence of HPV related throat cancers cases had more than doubled in the the U.S. in the years between 1980 and 2004. Furthermore, the percentage of oral and throat cancers that were caused by HPV grew even faster, since the number of tobacco related cancers declined over the same 20+ year period.
The Role of Oral Sex
How does a sexually transmitted virus end up associated with cancers located so far away from the genitals? The answer is probably oral sex. Several studies have shown a relationship between oral sex and the presence of HPV DNA in mouth and throat samples. Other studies have shown a relationship between oral sex and HPV positive throat cancers, particularly in those individuals who perform oral sex on men.
Taken as a group, these studies are yet another chilling reminder that oral sex is not safer sex. Various other sexually transmitted diseases can be spread by oral sex including herpes, gonorrhea, chlamydia, and syphilis. Safer sex techniques should therefore be used for oral sex as well as vaginal and anal sex. This is particularly true for individuals with genital herpes or HIV infections, since both viruses have been shown to predispose people to acquiring HPV.
The Problem with Testing
Scientists have questioned the role of different tests for HPV in predicting cancers at various sites. HPV is not an easy virus to meaningfully test for. Just finding HPV DNA in samples from a mouth swab does not necessarily mean that individuals will develop cancer. Conversely, many individuals with an HPV positive throat cancer biopsy test negative not only for HPV DNA in the cells of their mouths, but also for anti-HPV antibodies in their blood. In general, it is therefore extremely difficult to articulate the meaning of a positive, or negative, HPV test.
The Take Home Messages
- HPV, and in particular HPV 16, seems to play a role in the development of a significant number of cancers of the mouth and throat.
- Oral sex increases your risk of acquiring an HPV infection in your mouth or throat.
- Since the vast majority of HPV associated throat cancers seem to be caused by HPV 16, it is possible that the HPV vaccine might be useful for prevention.
- Although study results are mixed, it seems possible that smoking and alcohol use may interact with HPV infection to increase a person's risk of cancer.
Begum et al. (2005)"Tissue Distribution of Human Papillomavirus 16 DNA Integrationin Patients with Tonsillar Carcinoma" Clin Cancer Res 11(16):5694-9
Chaturvedi et al. (2011) "Human Papillomavirus and Rising Oropharyngeal Cancer Incidence in the United States" JCO Oct 3, 2011:; published online on October 3, 2011
D'Souza et al (2007)"Case–Control Study of Human Papillomavirus and Oropharyngeal Cancer" NJEM 356:1944-56.
Hererro et al. (2003)"Human Papillomavirus and Oral Cancer: The International Agency for Research on Cancer Multicenter Study" J. Natl Cancer Inst 95(23):1772-83
Kreimer et al. (2004) "Gender Differences in Sexual Biomarkers and Behaviors Associated With Human Papillomavirus-16, -18, and -33 Seroprevalence” Sex Trans Dis, V31(4):247-256
Kreimer et al. (2004) " Oral Human Papillomavirus Infection in Adults Is Associated with Sexual Behavior and HIV Serostatus." JID 189:686-98